Fix CSS Flexbox Collapse in Apple Mail (Desktop) — ActiveCampaign Guide for B2B Cold Outreach
B2B cold outreach templates demand maximum deliverability and a plain-text appearance. Heavy, broken CSS structures or HTML syntax issues trigger spam filters instantly. Below is the targeted integration guide to fix CSS Flexbox Collapse inside Apple Mail (Desktop) templates when using ActiveCampaign.
Technical Breakdown
Apple Mail (Desktop) uses the WebKit which lacks support for standard rendering rules. This causes CSS Flexbox Collapse elements to break or collapse when rendering templates.
ActiveCampaign Behaviors
ActiveCampaign's editor parses HTML template imports and automatically cleans inline attributes, which can break VML tags. Always use absolute styles and avoid relying on classes. For cold sales outreach, minimize VML structures and prioritize light, standard text blocks to maximize inbox placement on corporate enterprise filters.
Remediation Code Block
To resolve this, modern layouts must be compiled down to Outlook-compliant nested HTML table models. Each flex container becomes a table row, and each flex child becomes a table data cell (td) with explicit pixel or percentage widths. In your ActiveCampaign campaign manager, make sure you configure your links to run via %UNSUBSCRIBELINK%.
<table role="presentation" border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td width="50%" valign="top" style="padding: 20px;">Column 1</td>
<td width="50%" valign="top" style="padding: 20px;">Column 2</td>
</tr>
</table>Live Code Sandbox Test
How to Deploy inside ActiveCampaign
Copy the fixed VML or table wrapper code block from the remediation box above.
Insert an 'HTML block' from the layout builder panels. Avoid standard text boxes, as the ActiveCampaign parser might strip conditional MSO comment strings on saving.